In 1956, EB White, best known, perhaps, as the author of Charlotte's Web, wrote an essay called "The Ring of Time," in which he reflects on the nature of time while watching a circus vaulter practicing in the ring. The essay is often excerpted and excerpts usually only contain the section on the vaulter, but it's worth reading the whole essay.) White is entranced by the vaulter, by the very idea of her practice and its relationship to performance, and this gives him a place to begin talking about the nature of change over time. In the second section of the essay—this is the part that is left out of most anthologies—White reflects on time spent in the southern states just after the Supreme Court's Brown v. Board of Education decision and the changes he was anticipating for society.
The vaulter's practice is a metaphor for White. The vaulter creates the illusion of time running in circles, of beginning where she ends so that "the two were the same, and one thing ran into the next and time went around and around and got nowhere." The illusion is that time never passes and the world will never change. And yet, it is a practice—and in every practice the goal is always change and improvement. Even in a circle, there is forward momentum.